This invention relates to a loading device in a disc playback device for playing a disc such as a Compact Disc for the Compact Disc Digital Audio System and an optical type video disc.
A disc playback device generally includes a turntable provided on the chassis for rotating a disc thereon and an operation for loading a disc on the turntable from outside of the device and an operation for taking out the disc from the turntable are both automatically performed. A loading device for performing such loading and taking out of the disc is generally constructed in such a manner that in loading (i.e., during moving of the disc from an eject position to the turntable), the disc is moved horizontally along the chassis towards the turntable and, upon reaching of the disc above the turntable, the disc is lowered and set on the turntable whereas in ejecting (i.e., during moving of the disc from the turntable to the eject position), the disc is lifted from the turntable and moved horizontally along the chassis towards the eject position.
It is a question in designing such loading device how smoothly the operation for horizontally moving the disc and the operation for lowering and lifting the disc relative to the turntable should be performed.
By way of example of the disc playback device including such loading device, description will be made about a device shown in FIGS. 42 and 43 which has been proposed in Japanese Patent Application No. 193525/1984. This disc playback device is of a type in which a disc case housing a disc is loaded in the device.
In FIGS. 42 and 43, reference numeral 1 designates a disc magazine case housing a disc therein and reference numeral 2 a main body of the device for playing the disc in the disc magazine case 1. A clamper 4 and a holder 5 are supported on the upper surface of a chassis 3 of the main body 2. The clamper 4 is supported in its rear end portion on the chassis 3 via an arm 6 and pins 7, 8. The holder 5 is supported by holes 10, 10 formed in the clamper 4 via pins 9, 9 and also supported on the chassis 3 via an arm 11 and pins 12, 13. A spring 14 is provided between the clamper 4 and the holder 5 and a spring 16 is provided between the clamper 4 and an arm 15 supported on the chassis 3. On the side surface of the chassis 3 is supported a carrier 17 which is movable in the direction of arrows P1, P2. A rack 18 and a cam 19 are formed on the carrier 17. A shaft 20 is supported on the holder 20 and a loading pinion 21 is supported on this shaft 20 with a portion thereof being present in the holder 5. A carrier pinion 22 is also fixed on the shaft 20 which is meshable with a rack 18. A pin 23 engaging with a cam 19 is fixedly secured to the holder 5.
In the above described construction, when the carrier 17 is moved in the directions of the arrows P1, P2 by a drive system including a motor 24, the carrier pinion 22 is rotated so that the loading pinion 21 is rotated. When the disc magazine case 1 is inserted in the holder 5, the loading pinion 21 is meshed with a rack 25 formed on the side on the case 1 and thereby moves the case 1 in the directions of the arrows P1, P2. In the meanwhile, when the carrier 17 has moved in these directions, the pin 23 is lowered or lifted following the cam 19 by the force of the spring 16. The lowering or lifting of the pin 23 causes the clamper 4 and the holder 5 supported on the clamper 4 to be lowered or lifted relative to a turntable 26 provided on the upper surface of the chassis 3.
In the above described manner, the prior art disc playback device can move the disc magazine case 1 horizontally (the directions of the arrows P1, P2) and also downwardly or upwardly with the holder 5 thereby performing loading and ejecting of the disc housed in the disc magazine case 1.
For lowering and lifting the holder 5, the prior art device has adopted the construction according to which the clamper 4 is moved by causing the pin 23 to follow the cam 19 and the holder 5 is lowered and lifted with the clamper 4. This necessitates a very complicated construction. Besides, since the clamper 4 supporting the holder 5 is supported on the chassis 3 via the arm 6, the arm 6 moves in a pivotal motion in the directions of arrows P3, P4 when the holder 5 is lowered and lifted. This causes the holder 5 to move in the directions of the arrows P1, P2 when it is lowered and lifted with a result that a large space is required for allowing the movement of the holder 5.
It is, therefore, an object of the present invention to provide an improved loading device in a disc playback device of a simplified and space-saving construction.